Immunotherapy for GEC includes targeted blockade against immune checkpoints such as PD-1/PD-L1, cytotoxic T lymphocyte antigen-4 (CTLA-4), T cell immunoglobulin-3 (Tim-3), lymphocyte activation gene-3 (Lag-3) and chimeric antigen receptor T-cell (CAR-T) cell therapy; and therapeutic cancer vaccines. Here, LAG3 is linked to cancer.